docs: def playback(cls, filename):
          """
          .. testcode::
  
             import io
             import json
             import requests
             import httpretty
  
             with httpretty.record('/tmp/ip.json'):
                 data = requests.get('https://httpbin.org/ip').json()
  
             with io.open('/tmp/ip.json') as fd:
                 assert data == json.load(fd)
  
          :param filename: a string
          :returns: a `context-manager <https://docs.python.org/3/reference/datamodel.html#context-managers>`_
          """
          cls.enable()
  
          data = json.loads(open(filename).read())
          for item in data:
              uri = item['request']['uri']
              method = item['request']['method']
              body = item['response']['body']
              headers = item['response']['headers']
              cls.register_uri(method, uri, body=body, forcing_headers=headers)
  
          yield
          cls.disable()